Patient handling systems for medical imaging apparatus

Abstract

A patient handling systems (PHS) for medical imaging apparatus positions a patient on a patient bed in and out of an imaging field of view. A trolley carrying the patient bed translates linearly on a frame. The weight load of the patient bed is transferred to the frame along a load direction. The system incorporates a linear motor, having a rotor coupled to the trolley and a linear stator coupled to the frame in mutually opposed orientation, separated by a motor gap. The system also incorporates a linear motion encoder, having a sensing head coupled to the trolley and a linear encoder tape coupled to the frame in mutually opposed orientation, separated by a sensor gap. Both the motor and sensor gaps are oriented parallel to the weight load direction, to reduce likelihood of either gap variation attributable to load deflection of the frame.

Description

PATIENT HANDLING SYSTEMS FOR MEDICAL IMAGING APPARATUSPRIORITY CLAIM

[0001] This application claims the benefit of priority of United States Provisional Application Number 63 / 518,328, filed August 9, 2023, and entitled “Highly Integrated Floor Axis for Constant Deflection PHS” which is incorporated by reference herein.TECHNICAL FIELD

[0002] The disclosure relates to patient handling systems (PHS) for diagnostic medical imaging apparatus. More particularly, the disclosure relates to motorized patient handling systems for positioning of patients in and out of an imaging field of view of the imaging apparatus, such as an imaging tunnel.BACKGROUND

[0003] Diagnostic medical imaging apparatuses include, by way of non-limiting example computed tomography (CT), two-dimensional digital radiography (DR), positron emission tomography (PET), magnetic resonance imaging (MRI), PET / CT, and PET / MRI modalities. FIGs. 1-4 depict a known PET scanner 20 that includes a toroidal-shaped, rotating gantry structure 22, with a patient tube 24 through which is inserted a cantilever-supported patient bed 26. Within patient tube 24, the scanner 20 establishes an imaging field of view (FoV) with a horizontal scan axis. A motorized patient handling system (PHS) 28, selectively translates the cantilever-mounted patient bed 26 linearly on a floor-mounted frame 30, advancing and retracting the latter in and out of the patient tube 24. Frame 30 supports patient bed 26 and patient weight load. The PHS 28 is generally suitable for use with various modalities of medical imaging apparatus that require translation of a patient bed within an imaging FoV established within a patient tube 24.

[0004] The horizontal scan axis of the PET scanner 20 is axially aligned with the longitudinal axis X of the PHS 28 and its patient bed 26. Given the cantilevered mounting orientation of the patient bed 26 on the frame 30 it is desirable to maintain the same constant deflection in the direction of the patient load (vertical axis Z) throughout the full translation range of the bed on the frame. Such constant deflection enhances the image quality of the scan. In PET-CT systems where the two respective field of views (FoV) are in series within a common patient tube that is generally longer than that of single modality PET or CT systems, its patient bed must have sufficient longitudinal length in the X axis direction to be able to translate the patient fully through both of the scanner FoV’s. It is desirable that both FoV’s have the same constant deflection. This property improves the image quality of each of the respective FoV’s itself as well as the superimposition of the image data of both FoV’s for diagnostic evaluation of the patient.

[0005] Referring again to FIGs. 1-4. in order to optimize constant load deflection of patient bed 26 (Z axis) throughout its full translation range (X axis) of the PHS 28. frame 30 has been constructed with two planar plates. Prior art construction of the floor axis of a PET patient bed consists of one or more (here, two) flat metal plates 32 and 34, which are retained by a matrix array of anchoring studs 36 that are embedded within, glued to, and projecting from the floor 38 of the imaging room. Typically, plates 32 and 34 are constructed of aluminum. A pair of linear rails 40 having a respective mounting surface 42 are screwed onto these two plates 32 and 34 and are aligned with the longitudinal axis X of the PHS 28. A corresponding pair of runner blocks 44 are slidably coupled to the respective linear rails 40. The runner blocks 44 are coupled to a trolley 46 that retains the patient bed 26. The runner blocks 44 are pre-tensioned to compensate for a specified patient load to be applied to patient bed 26 and trolley 46, calculated to offset the patient load that would otherwise deflect the linear rails 40 downwardly in the Z direction. Notwithstanding runner block 44 pretensioning. deflection loads attributable to patient load and / or floor deflection, and / or torsional offset loads of the patient on the cantilevered patient bed 26 may twist the trolley 46 and its attached runner blocks orientation relative to its linear rail. This twisting load effectively applies a translation-resisting clamping force between therunner blocks and the rail that is in turn transferred as a buckling force on the flat plates 32 and 34. Buckling forces applied to the flat plates 32 and 34 is resisted by a relatively large number of anchoring studs 36. Typically, 64 or more anchoring studs 36 are required for installation of known frames 30, which is approximately 22 anchoring studs per meter of frame length. Accordingly, the installation effort to drill and affix this large number of anchoring studs is relatively high.

[0006] The patient bed 26 of the known PHS 30 is translated by a drive system comprising a linear motor 48 oriented between the linear rails 40, with a rotor 50 coupled to the trolley and an opposing, flat linear stator 52 coupled to the mounting plates 32 and 34. Linear stator 52 comprises a linear array of magnets. Motor air gap gm of approximately 0.5 to 1 mm, is established between the opposed, horizontally oriented surfaces of the respective rotor 50 and the linear stator 52, with the gap dimension susceptible to variation by applied patient load on the patient bed 26. ft follows that if the frame 30 and its linear rails 40 deform due to patient load while the patient bed 26 and the trolley 46 translate along the PHS 30, the linear motor gap also changes. Motor 48 gap variations along the translation length of the patient bed 26 adversely varies motor drive force. Under extreme conditions, the rotor 50 and the linear stator 52 components may contact each other, damaging the linear motor 48. Another potential motor drive force variation can be caused by buildup of contaminant particles within the patient scanning room that are deposited on the upper facing surface of linear stator 52.

[0007] Linear motion encoder 54 of the PHS 28 drive system is oriented horizontally between the trolley 46 and the plates 32 and 43 of the frame 30. The linear motion encoder 54 provides trolley 46 / patient bed 26 translation position information to a controller (not shown) that among other things controls operation of the linear motor 48. The linear motion encoder 54 comprises a magnetic or optical linear encoder tape 56 oriented horizontally on the plates. 32 and 34 and a corresponding magnetic or optical sensing head 58 that is coupled to one of the runner blocks 44 or the trolley 46. As with the sensitivity of the air gap of the linear motor 48, variance of the air gap gebetween the encoder tape 56 and the sensing head 58, caused by particle contamination, bending deflection between the runner blocks 44 and / or the trolley 46 lead to potential operational problems of the PHS 28.

[0008] The PHS 28 is enclosed by side covers 60 that are screwed to the sides of the plates 32 and 34. Over the frame rails 40, the linear motor 48 and the tape encoder 44 a pair of roll covers 62 and 64 compnsing pluralities or joined, laterally oriented stnps or slats, respectively have free ends affixed to opposite ends of the trolley 46 and rolled fixed ends affixed to the frame 30. The lateral edges of each respective roll cover 62 and 64 ride in grooves 66 of the side covers 60. The fixed ends of the roll covers are rolled on spindles extending axial length of the frame 30, enlarging axial footprint of the PHS 28. If the frame 30 buckles or deforms due to patient load applied to the patient bed 26 along the bed’s length of travel one or both of the roll covers 62 and 64 may jam within the grooves 66 of the side covers 60, which increases load on the linear motor 48. Rubbing friction between the lateral edges of each respective roll cover 62 and 64 and the grooves 66 of the side covers generate noise during the patient bed 26 translation. The previously described plurality of lateral strip or slat segment construction of the roll covers 62 and 64 comprise many interfacing edges between strips that are susceptible to debris collection.

[0009] The known PHS 28 incorporates a drag chain 68 oriented laterally outboard of the linear rails 40 in a relatively small compartment bounded by one of the lateral covers 60.SUMMARY

[0010] A patient handling systems (PHS) for a medical imaging apparatus positions a patient on a patient bed in and out of an imaging field of view. A trolley carrying the patient bed translates linearly on a frame. The weight load of the patient bed is transferred to the frame along a weight load direction. The system incorporates a linear motor, having a rotor coupled to the trolley and a linear stator coupled to the frame in mutually opposed orientation, separated by a motor gap. The system also incorporates at least one linear motion encoder, having a sensing head coupled to the trolley and a linear encoder tape coupled to the frame in mutually opposed orientation, separated by a sensor gap. Both the motor and sensor gaps are oriented parallel to the weight load direction, to reduce likelihood of either gap variation attributable to load deflection of the frame.

[0011] Exemplary embodiments described herein are utilized in a patient handling system (PHS) for a medical imaging apparatus, comprising a frame with a longitudinal length, defining a central longitudinal axis that is aligned with the scanning axis of the imaging apparatus, and an upper surface. A pair of first and second linear rails are respectively coupled to the frame, oriented parallel to the central longitudinal axis. A pair of first and second runner blocks are respectively slidably coupled to the first and second linear rails. A trolley is commonly coupled to the first and second runner blocks. The trolley is slidably mounted over the upper surface of the frame and translatable along the central longitudinal axis. A cantilevered patient bed is coupled to the trolley, so that weight load of the patient bed is transferred to the frame along a first load direction through the trolley, the first runner block and the first linear rail and along a second load direction through the trolley, the second runner block and the second linear rail. The PHS incorporates at least one linear motor, having a rotor and a linear stator in opposed orientation, separated by a motor gap. The rotor is coupled to the trolley and the linear stator is coupled to the frame in orientation parallel to the central longitudinal axis. The motor gap is oriented parallel to at least one of the first or second load directions, so that its gap dimension does not change due to variations in the patient load. The PHS has at least one linear motion encoder, having a sensing head and a linear encoder tape in opposed orientation, separated by an encoder gap. The sensing head is coupled to the trolley or one of the first or the second runner blocks, and the linear encoder tape is coupled to the frame in orientation parallel to the frame central longitudinal axis. The encoder gap is oriented parallel to at least one of the first or second load directions, so that its gap dimension does not change due to variations in the patient load.

[0012] Exemplary embodiments of the disclosure feature a patient handling system for a medical imaging apparatus. The PHS includes a frame with a longitudinal length, defining a central longitudinal axis and an upper surface. The frame has opposed, laterally spaced, outer first and second walls, commonly joined and bridged by a transverse-oriented third wall. Fourth and fifth walls of the frame are oriented inboard of the first and second walls and they are commonly coupled by the transverse third wall. All of said first through fifth walls are oriented parallel to the central longitudinal axis. The third, fourth and fifth walls collectively define a u-shaped, open cavity' that is in communication with the upper surface of the frame. A transverse oriented sixth wall joins the outer, first wall and the inboard, fourth wall, and a transverse oriented seventh wall joins the outer, second wall and the inboard, fifth wall. The sixth and seventh walls form lateral edges of the cavity that are parallel to the longitudinal axis. The frame is constructed as a metal monolithic block, formed by a metal extrusion process. First and second linear rails are respectively coupled to the respective first and second walls, and they are oriented parallel to the central longitudinal axis. First and second runner blocks are respectively slidably coupled to the first and second linear rails. A trolley is commonly coupled to the first and second runner blocks; it is slidably mounted on the upper surface of the frame and translatable along the central longitudinal axis by virtue of the runner blocks sliding along the linear rails. A cantilevered patient bed is coupled to the trolley, so that weight load of the patient bed is transferred to the frame along a first load direction through the trolley, the first runner block and the first linear rail and along a second load direction through the trolley, the second runner block and the second linear rail. The PHS has at least one linear motor, with a rotor and a linear stator in opposed orientation, separated by a motor gap. The rotor is coupled to the trolley by a motor support extending into the cavity7. The linear stator is coupled to the fourth wall or the fifth wall of the frame, in orientation parallel to the central longitudinal axis, with the motor gap oriented parallel to at least one of the first or second load directions. The PHS has at least one linear motion encoder, having a sensing head and a linear encoder tape in opposed orientation, separated by an encoder gap. The sensing head is coupled to the trolley or one of the first or the second runner blocks and the linear encoder is coupled to the frame in orientation parallel to the frame central longitudinal axis, with the encoder gap oriented parallel to at least one of the first or second load directions.

[0013] In some embodiments, the first and second linear rails have respective first and second mounting surfaces that are coupled to the respective first and second walls with the first and second linear rails oriented so that the respective first and second load directions are parallel to and apply a shearing load on the respective mounting surfaces.

[0014] In some embodiments, the first and second linear rails have respective first and second mounting surfaces that are coupled to the respective first and second walls with the first and second linear rails oriented so that the respective first and second load directions are oriented normal to and apply a tensile load to the respective mounting surfaces.

[0015] Other exemplary embodiments of the disclosure feature a continuous planar, flexible belt covering the open cavity of the frame. Respective longitudinal ends of the belt are coupled to respective longitudinal ends of the frame. The belt passes between opposed rollers that are coupled to the trolley. A first drip rail is coupled to the sixth wall, and a second drip rail coupled to the seventh wall. Both drip rails are coupled to the outer surface of the frame along lateral edges of the cavity, below lateral edges of the flexible belt.

[0016] Additional exemplary embodiments of the disclosure feature a drag chain oriented in the frame cavity for providing electrical power to the linear motor and / or the trolley. One end of the drag chain is coupled to the frame and the other end of the drag chain is coupled to the trolley.

[0017] The respective features of the exemplary embodiments of the disclosure that are described herein may be applied jointly or severally in any combination or subcombination.BRIEF DESCRIPTION OF DRAWINGS

[0018] The exemplary embodiments of the disclosure are further described in the following detailed description in conjunction with the accompanying drawings, in which:

[0019] FIG. 1 is a perspective view of a known medical imaging apparatus, including its patient handling system (PHS);

[0020] FIG. 2 is an isometric top view' of a frame of the known PHS of FIG. 1;

[0021] FIG. 3 is an isometric bottom view of the frame of the known PHS of FIG. 1:

[0022] FIG. 4 is a cross-sectional view of the frame of the known PHS. taken along 4- 4 of FIG. 3;

[0023] FIG. 5 is an orthogonal view of an embodiment of the PHS of this disclosure, including its frame, translatable trolley and patient bed mounted on the trolley;

[0024] FIG. 6 is an axial cross-sectional view of the frame and trolley of the PHS of FIG. 5, taken along 6-6 thereof, with the patient bed shown in outline form in its "‘parked” and “fully inserted” translation positions;

[0025] FIG. 7 is a transverse cross-sectional view of the frame of the PHS of FIG. 5, taken along 7-7 thereof;

[0026] FIG. 8 is a partial cross-section of the frame, trolley and patient bed of FIG. 5, taken along 8-8 thereof;

[0027] FIG. 9 is an axial cross-section of the frame, trolley and patient bed of FIG. 5, taken along 8-8 thereof; and

[0028] FIG. 10 is a transverse cross-sectional view of an alternative embodiment of a PHS of this disclosure, showing the frame and trolley.

[0029] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures.DESCRIPTION OF EMBODIMENTS

[0030] Exemplary embodiments of the disclosure are utilized in a patient handling system (PHS) for a medical imaging apparatus. The PHS includes a frame with a longitudinal length, defining a central longitudinal axis that is aligned with the scanning axis of the imaging apparatus, and an upper surface. First and second linear rails are respectively coupled to the frame, oriented parallel to the central longitudinal axis. The first and second runner blocks are respectively slidably coupled to the firstand second linear rails. A trolley is commonly coupled to the first and second runner blocks. The trolley is slidably mounted on the upper surface of the frame and translatable along the central longitudinal axis. A cantilevered patient bed is coupled to the trolley, so that weight load of the patient bed is transferred to the frame along a first load direction through the trolley, the first runner block and the first linear rail and along a second load direction through the trolley, the second runner block and the second linear rail. In some embodiments, a three-dimensional frame structure resists deflection caused by patient loads throughout the translation range of the PHS. The PHS incorporates at least one linear motor, having a rotor and a linear stator in opposed orientation, separated by a motor gap. The rotor is coupled to the trolley and the linear stator is coupled to the frame in orientation parallel to the central longitudinal axis. The motor gap is oriented parallel to at least one of the first or second load directions, so that its gap dimension does not change due to variations in the patient load. The PHS has at least one linear motion encoder, having a sensing head and a linear encoder tape in opposed orientation, separated by an encoder gap. The sensing head is coupled to the trolley or one of the first or the second runner blocks, and the linear encoder tape is coupled to the frame in orientation parallel to the frame central longitudinal axis. The encoder gap is oriented parallel to at least one of the first or second load directions, so that its gap dimension does not change due to variations in the patient load. In other embodiments, a continuous, planar flexible belt covers the internal components of the PHS within the frame, such as the linear rails, the linear motor and the linear motion encoder throughout the entire translation range of the trolley and the patient bed.

[0031] In accordance with embodiments of the invention, the frame’s three- dimensional profile allows a significantly reduced number of ground anchors, which reduces installation time. In some embodiments, the frame is an intrinsically rigid, metal monolithic block formed by an extrusion process. In some embodiments, the frame profile is designed in such a way that it can be machined in one single clamping operation on a machining table. The machined interfaces are thus arranged with high precision to each other, which enhances component alignment during assembly, and higher inter-component rigidity after assembly. In some embodiments, the highly integrated, three-dimensional frame design includes all interfaces to add-on parts,which reduces the number of components enormously. Thus, the assembly effort of add-on parts is reduced. The high inherent rigidity of the frame reduces the torsional deflection caused by patient loads that might otherwise clamp the linear rails and the runner blocks, thus reducing drive load on the linear motor. In addition, a rigid basic of the frame profile enables the use of non-preloaded, non-backlash-free, linear rails and runner blocks. This also significantly reduces the tendency to increase travel forces on the linear motor due to tensions of the linear rails.

[0032] In various embodiments of this disclosure, both the linear motor and the linear motion encoder are oriented arranged in such a way that their respective air gaps are is oriented vertically, so that those gaps are parallel to the applied patient load on the patient bed. Such vertical alignment of both air gaps allows debris particles to fall through the gaps instead of remaining on exposed horizontal surfaces of the linear stator or the encoder tape components. Expressed another way, the motor and encoder air gaps are oriented orthogonally to the main deflection direction of the frame and its linear rails as well as those of the trolley and the runner blocks, sand thus independent of their deformation attributable to patient weight on the cantilevered patient bed.

[0033] In various embodiments, the trolley, its associated vertical carrier structure, to which the patient bed is coupled in cantilever-like fashion and the continuous planar, flexible belt covering the open cavity in the frame between the linear rails, with respective longitudinal ends of the belt coupled to respective longitudinal ends of the frame. In some embodiments, first and second drip rails coupled to the outer surface of the frame along lateral edges of the open cavity, below lateral edges of the flexible belt. In embodiments including both the flexible belt and the drip rails, liquids dropping onto the PHS drain laterally away from the covered open cavity over the lateral edges of the frame or collect in the drip rails. The embodiments with the flexible belt alone or in combination with the drip rails are easier to clean than the prior art PHS of FIGs. 1-4, with multi-slat roll covers retained within lateral cover grooves of the side covers. Also, omission of the prior art roll cover and lateral cover grooves interfaces eliminates roller bind noise and / or varying motor load needed to overcome the frictional binding at the interfaces.

[0034] FIGs. 5 and 6, in combination, show a medical diagnostic imaging scanner 70 with a gantry772, a patient tube 74, and a patient bed 76. The patient handlingsystem (PHS) 78 of the present disclosure is coupled to and supports, in cantilever fashion, the patient bed 76. The imaging scanner 70 defines a field of view (FoV) with a scanning axis in the Y direction within patient tube 74. The PHS 78 comprises a frame 80 with a frame upper surface 81. Frame 80 has a longitudinal length in the Y direction and defines a longitudinal axis that is aligned with the scanning axis of the imaging scanner 70. Anchoring studs 82 are embedded in the scanner room floor 84; they anchor the frame 80 to the floor.

[0035] The PHS 78 translates the patient bed 76 between a "‘park” position 86, for positioning a patient on the patient bed and a ‘Tull travel” position 88 where the patient bed is fully inserted into the patient tube 74. Patient bed 76 is supported in cantilevered fashion by a vertical carrier 90 that selectively positions the patient bed in the vertical or Z direction. The vertical carrier 90 is coupled to a trolley 92 that translates along the longitudinal axis of the frame 80, which longitudinal axis is on the same vertical plane in the Z direction as the longitudinal axis of the patient bed. The PHS 78 supports the patient weight load Lp. In preparation for a patient imaging scan, the PHS 78 maneuvers the longitudinal axis of the patient bed 76 in vertical and longitudinal co-alignment with the scanning axis of the imaging scanner 70 and maintains the co-alignment as the patient bed is translated in the Y direction through the patient tube. Deviations in such scanning axis and patient bed 76 longitudinal axis co-alignment degrade quality of the scan image. PHS embodiments of this disclosure maintain PHS longitudinal axis and scanning axis co-alignment throughout translation range between the “park” position 86 and the “full travel” position 88 of the patient bed 76.

[0036] In the PHS 78 embodiment of FIGs. 5 and 6, frame 80 is split into front 94 and rear 96 portions for transport and eventual installation in a patient imaging facility. In some embodiments, pre-assembled trolley 92, vertical carrier 90 and patient bed 76 components are mounted on the front portion 94 of the frame 80. Upon assembly at the patient imaging facility, the front 94 and rear 96 portions are co-aligned along a common central longitudinal axis in the Y direction and joined by one or more frame plates 98 to form the unified frame 80.

[0037] In the PHS 78 embodiment of FIGs. 7-9, its frame 80 has an upper surface 81 and it defines a central longitudinal axis in the Y direction. In this embodiment, frame80 is constructed as a metal monolithic block, formed by a metal extrusion or metal casting process. In some embodiments, such as shown in FIG. 6, the assembled frame 80 is a split frame that comprises front 94 and rear 96. co-joined monolithic blocks. In some embodiments, the frame is a unified structure of welded subcomponents.

[0038] In FIG. 7, frame 80 has opposed, laterally spaced, outer first 100 and second 102 walls, commonly joined and bridged by a transverse-oriented third wall 104. In this embodiment, the third wall 104 comprises a pair of upper and lower, horizontally oriented wall segments with a mid-span, vertical column segment. In some embodiments there is a single third wall without multiple wall segments. In this embodiment, the fourth 106 and fifth 108 walls of the frame are oriented inboard of the first 100 and second 102 walls and they are commonly coupled by the upper horizontal segment of the transverse third wall 104. All of said first 100 through fifth 108 walls are oriented parallel to the central longitudinal axis. The third 104, fourth 106, and fifth 108 walls collectively define a u-shaped, open cavity 110 that is in communication with the upper surface 81 of the frame 80. A transverse oriented sixth wall 112 joins the outer, first wall 100 and the inboard, fourth wall 106; and a transverse oriented seventh wall 114 joins the outer, second wall 102 and the inboard, fifth wall 108. The sixth 112 and seventh 114 walls form lateral edges of the cavity 110 that are parallel to the longitudinal axis.

[0039] First 120 and second 122 linear rails are respectively coupled to the respective first 100 and second 102 walls of the assembled frame 80 by their respective first 124 and second 126 mounting surfaces, and their respective longitudinal axes are oriented parallel to the central longitudinal axis of the frame of the PHS 78. In the embodiment of FIG. 7, the mounting surfaces 124 and 126 of the linear rails are oriented normal to applied, tensile, patient weight load Lp. Respective first 130 and second 132 runner blocks are respectively slidably coupled to the first 120 and second 122 linear rails. Trolley 92 is commonly coupled to the first 130 and second 132 runner blocks; it is slidably mounted over the upper surface 81 of the frame 80 and it is translatable along the central longitudinal axis (Y direction) by virtue of those runner blocks sliding along the first 120 and second 122 linear rails. The cantilevered patient bed 76 is coupled to the trolley 92, so that a first portion of the weight load Lp of the patient bed (including weight of a patient) is transferred to the frame 80 along a first loaddirection through the trolley, the first runner block 130 and the first linear rail 120 as a tensile load. A second portion of the tensile load Lp of the patient bed is transferred to frame 80 and along a second load direction through the trolley 92, the second runner block 132, and the second linear rail 122, also as a tensile load.

[0040] The PHS 78 has at least one linear motor 140. The linear motor 140 has a rotor 146 and a linear stator 148 that are in opposed orientation, separated by a motor gap gm. The rotor 146 and its supporting structure of the linear motor 140 is coupled to the trolley 92 by a motor support 142 that extends into the u-shaped, open cavity 110 formed within frame 80. The linear stator 148 is coupled to the fourth wall 106 or the fifth wall 108 of the frame 80, in orientation parallel to the central longitudinal axis, with the motor gap gm oriented parallel to at least one of the first and second load directions, i.e., in FIG. 7 downwardly in the Z direction toward the floor 84. Some embodiments of the PHS of this disclosure comprise two linear motors that are oriented in parallel to each other and under common drive control system (not shown).

[0041] The PHS 78 has at least one linear motion encoder 150, having a sensing head 152 and a linear encoder tape 154 in opposed orientation, separated by an encoder gap ge. In FIG. 7, the sensing head 152 is coupled to the first runner block 130. In other embodiments the sensing head is coupled to the trolley or to the second runner block. Linear encoder tape 154 is coupled to frame 80 in orientation parallel to the frame central longitudinal axis, with the encoder gap ge oriented parallel to at least one of the first and second load directions of the patient bed load Lp. Some embodiments of the PHS of this disclosure comprise two linear motion encoders that are oriented in parallel to each other for providing redundant patient bed translation position to the drive control system (not shown).

[0042] Referring to FIGs. 7-9, the open cavity 110 in the frame 80 is covered by a continuous, flexible belt 160, with first 162 and second 164 lateral edges. Terminal longitudinal ends of the belt 160 are coupled to the longitudinal ends of the frame 80. The continuous, uninterrupted belt 160 is threaded through opposed belt rollers 168 within the trolley 92 and the vertical carrier 90 that support the patient bed 76. Thus, the trolley 92 translates along the frame 80 while the continuous belt covers the open cavity 110 in front of and behind the trolley. In some embodiments, the continuousbelt comprises spliced sections of shorter length belts. Drip rails 172 and 174 oriented below the belt 160 collect any spilled fluids that may fall from the first 162 and second 164 lateral edges of the belt. The combination of the continuous belt 162 and the drip rails 172 and 174 are oriented to capture any fluids falling on the upper surface 81 of the PHS 78, yet their vertical separation prevents frictional binding as might otherwise occur if they are in direct contact with each other. Advantageously, the smooth outer surfaces of the continuous belt 162 and the drip rails 172 and 172 are easily cleaned.

[0043] Referring to FIG. 9, the PHS 78 includes a drag chain 180 for powering the motorized trolley 92 and the vertical carrier 90, among other components. The drag chain 180 is oriented in the open cavity 110 of the frame 80, below the linear motor 140. In FIG. 9, a fixed end 182 of the drag chain 180 is coupled to the frame 80 at the bottom of the open cavity 110 at approximately the longitudinal center of the frame, while a translating end 184 of the chain is coupled to the trolley 92. In this figure, the serpentine chain is folded vertically throughout trolley translation (i.e., in the vertical or Z direction). In other embodiments, the serpentine drag chain folded horizontally throughout trolley translation (i.e., in the lateral or X direction).

[0044] Referring to FIGs. 5 and 7, the frame 80 of the PHS 78 incorporates a plurality of integrally formed floor lugs 190 for anchoring the anchoring studs 82 to the imaging room floor 84. The floor lugs 190 and the exposed heads of the anchoring studs 82 are covered by lug covers 192.

[0045] The PHS 198 and trolley 199 embodiment of FIG. 10 orients the linear rails 220 and 222 laterally outwardly from frame 200, as compared to the embodiment of FIG. 7, wherein its linear rails 120 and 122 are oriented downwardly from frame 80. In the PHS 198 embodiment, the aforementioned first 220 and second 222 linear rails are respectively coupled to respective first 202 and second 204 walls of the assembled frame 200 by their respective first 224 and second 226 mounting surfaces, and they are oriented parallel to the central longitudinal axis. The respective rail mounting surfaces 224 and 226 are oriented parallel to the applied patient weight load Lp on the trolley 199; that applied load generates a shearing force on the first 220 and second 222 linear rails and their respective mounting surfaces.

[0046] In the embodiment of FIG. 10, frame 200 has an upper surface 201, opposed, laterally spaced, outer first 202 and second 204 walls, commonly joined and bridged by a transverse-oriented third wall 206. In this embodiment, the fourth 208 and fifth 210 walls of the frame 200 are oriented inboard of the first 202 and second 204 walls and they are commonly coupled by the transverse third wall 206. All of said first 202 through fifth 210 walls are oriented parallel to the central longitudinal axis. The third 206, fourth 208, and fifth 210 walls collectively define a u-shaped, open cavity 211 that is in communication with the upper surface 201 of the frame 200. A transverse oriented sixth 212 wall joins the outer, first wall 202 and the inboard, fourth wall 208, and a transverse oriented seventh wall 214 joins the outer, second wall 204 and the inboard, fifth wall 210. The sixth 212 and seventh 214 walls form lateral edges of the u-shaped cavity 21 1 that are parallel to the longitudinal axis. The frame 200 of the PHS 198 incorporates a plurality of integrally formed floor lugs 219 for anchoring the anchoring studs 82 to the imaging room floor 84. The floor lugs 190 and the exposed heads of the anchoring studs 82 are covered by lug covers 229.

[0047] First 227 and second 228 runner blocks are respectively slidably coupled to the first 220 and second 222 linear rails. Trolley 199 is commonly coupled to the first 227 and second 228 runner blocks; it is slidably mounted above the upper surface 201 of the frame 200 and it is translatable along the central longitudinal axis (Y direction) by virtue of those runner blocks sliding along the first 220 and second 222 linear rails. The cantilevered patient bed is coupled to the trolley 199, so that a first portion of the weight load Lp of the patient bed (including weight of a patient) is transferred to the frame 200 along a first load direction through the trolley, the first runner block 227 and the first linear rail 220 as a shearing load. A second portion of the tensile load Lp of the patient bed is transferred to frame 200 and along a second load direction through the trolley 199, the second runner block 228, and the second linear rail 222, also as a shearing load.

[0048] The PHS 200 has at least one linear motor 232 with a rotor 234 and a linear stator 236 that are in opposed orientation, separated by a motor gap gm. The rotor 234 is coupled to the trolley 199 by a motor support 230, and extends into the u-shaped, open cavity 211 formed within frame 200. The linear stator 236 is coupled to the fourth wall 208 or the fifth wall 210 of the frame 200, in orientation parallel to thecentral longitudinal axis, with the motor gap gm oriented parallel to at least one of the first and second load directions, i.e., in FIG. 10 downwardly in the Z direction toward the floor 84. Some embodiments of the PHS of this disclosure comprise two linear motors that are oriented in parallel to each other and under common drive control system (not shown).

[0049] The PHS 198 has at least one linear motion encoder 240, having a sensing head 242 and a linear encoder tape 244 in opposed orientation, separated by an encoder gap ge. In FIG. 10, the sensing head 242 is coupled to the second runner block 228. In other embodiments, the sensing head is coupled to the trolley 199 or to the first runner block 227. Linear encoder tape 244 is coupled to frame 200 in orientation parallel to the frame central longitudinal axis, with the encoder gap georiented parallel to at least one of the first and second load directions of the patient bed load Lp. Some embodiments of the PHS of this disclosure comprise tw o linear motion encoders that are oriented in parallel to each other for providing redundant patient bed translation position to a drive control system (not shown) of the PHS 198.

[0050] As with the PHS 78 embodiment of FIG. 7, the open cavity 211 frame 200 is covered by a continuous, flexible belt 250. Terminal longitudinal ends of the belt 250 are coupled to the longitudinal ends of the frame 200. In some embodiments, the belt 250 comprises spliced smaller belt segments. The continuous, uninterrupted belt 250 is threaded through opposed belt rollers within the trolley 199 and the vertical carrier that supports the patient bed. Thus, trolley 199 translates along the frame 200 while the continuous belt 250 covers the open cavity 211 in front of and behind the trolley. Drip rails 252 and 254 oriented below the belt 250 collect any spilled fluids that mayfall from the belt. The combination of the continuous belt 250 and the drip rails 252 and 254 are oriented to capture any fluids falling on the upper surface 201 of the PHS 198, yet their vertical separation prevents frictional binding as might otherwise occur if they are in direct contact with each other. Advantageously, the smooth outer surfaces of the continuous belt 250 and the drip rails 252 and 254 are easily cleaned.

[0051] Various embodiments of the PHS of this disclosure provide at least the following range of benefits, alone or in combination, which are not provided for in the prior art PHS 28 of FIGs. 1-4:

[0052] Approximately a fi fty percent (50%) reduction in the number of anchoring studs fixing the frame to the scanning room floor, shortening PHS installation time and complexity.

[0053] Reduced likelihood of clamping of the linear rails and their associated runner blocks caused by patient load deflection of the frame structure, thus reducing translation load on the linear motor drive system.

[0054] Three-dimensional, integral frame construction, compared to the prior art, flat plate construction, providing increased frame rigidity, allowing use of less massive linear rails and runner blocks and less overall deflectional variation of the patient bed axis with the scanning axis of the imaging scanner along patient bed translation. Less deflectional variation along patient bed translation of the PHS leads to better image quality of the imaging system.

[0055] Orientation of liner motor and linear encoder air gaps orthogonal to the applied patient load on the linear rails, runner blocks and trolley so that those air gaps are parallel to the applied patient load direction, thereby avoiding patient load influences on those air gaps. This reduces undesired variations in motor or encoder operation and avoids potential direct, damaging impact contact between their associated components under extreme patient load forces on the frame.

[0056] Use of a continuous planar, flexible belt covering the frame open cavity, with or without drip rails, replacing prior art roll covers, thus eliminating roll cover binding and hygienic cleaning challenges.

[0057] The drag chain is oriented in the relatively large cavity between the linear rails, allowing sufficient volume for vertical or horizontal, non-binding chain motion, compared to the relatively smaller volume space of the prior art PHS. outboard of the linear rails within the side cover.

[0058] Although various embodiments that incorporate the disclosure have been shown and described in detail herein, others can readily devise many other varied embodiments that still incorporate the claimed disclosure. The disclosure is not limited in its application to the exemplary' embodiment details of construction and the arrangement of components set forth in the description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or of being conducted in many ways. Also, it is to be understood that the phraseology' andterminology used herem is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical or electrical connections or couplings.

Claims

CLAIMSWhat is claimed is:

1. A patient handling system for a medical imaging apparatus, comprising: a frame with a longitudinal length, defining a central longitudinal axis, and an upper surface; first and second linear rails respectively coupled to the frame, oriented parallel to the central longitudinal axis; first and second runner blocks, respectively slidably coupled to the first and second linear rails; a trolley commonly coupled to the first and second runner blocks, the trolley slidably mounted over the upper surface of the frame and translatable along the central longitudinal axis; a cantilevered patient bed coupled to the trolley, so that weight load of the patient bed is transferred to the frame along a first load direction through the trolley, the first runner block and the first linear rail and along a second load direction through the trolley, the second runner block and the second linear rail; at least one linear motor, having a rotor and a linear stator in opposed orientation, separated by a motor gap, the rotor coupled to the trolley and the linear stator coupled to the frame in orientation parallel to the central longitudinal axis, with the motor gap oriented parallel to at least one of the first or second load directions; and at least one linear motion encoder, having a sensing head and a linear encoder tape in opposed orientation, separated by an encoder gap, the sensing head coupled to the trolley or one of the first or the second runner blocks, and the linear encoder tape coupled to the frame in orientation parallel to the frame central longitudinal axis, with the encoder gap oriented parallel to at least one of the first or second load directions.

2. The patient handling system of claim 1, further comprising the first and second linear rails having respective first and second mounting surfaces coupled to the frame, the first and second linear rails oriented so that the respective first and second load directions are parallel to and apply a shearing load on the respectivemounting surfaces.

3. The patient handling system of claim 1, further comprising the first and second linear rails having first and second mounting surfaces coupled to the frame, the linear rails oriented so that the respective first and second load directions are oriented normal to and apply a tensile load to the respective mounting surfaces.

4. The patient handling system of claim 1, the frame comprising: opposed, laterally spaced, outer first and second walls, commonly joined and bridged by a transverse-oriented third wall, all of the first, second and third walls parallel to the central longitudinal axis; the first and second linear rails respectively coupled to the respective first and second walls; and a u-shaped, open cavity that is in communication with the upper surface of the frame, the open cavity oriented between the first and second walls.

5. The patient handling system of claim 4, the frame further comprising respective fourth and fifth walls oriented inboard of the first and second walls that are commonly coupled by the transverse third wall, all of said first through fifth walls parallel to the central longitudinal axis, the third, fourth and fifth walls collectively defining the u-shaped, open cavity that is in communication with an upper surface of the frame.

6. The patient handling system of claim 5, further comprising the linear motor oriented in the cavity, with the rotor coupled to the trolley by a motor support extending into the cavity and the linear stator coupled to either the fourth wall or the fifth wall.

7. The patient handling system of claim 5, further comprising the sensing head coupled to one of the runner blocks and the linear encoder coupled to one of the first or second or fourth or fifth walls.

8. The patient handling system of claim 5, the frame further comprising a transverse oriented sixth wall joining the outer, first wall and the inboard, fifth wall, and a transverse oriented seventh wall joining the outer, second wall and the inboard, fifth wall.

9. The patient handling system of claim 8, the frame further comprising a metal monolithic block formed by a metal extrusion process.

10. The patient handling system of claim 5, further comprising the first and second linear rails having respective first and second mounting surfaces coupled to the respective first and second walls; the first and second linear rails oriented so that the respective first and second load directions are parallel to and apply a shearing load on the respective mounting surfaces.

11. The patient handling system of claim 5, further comprising the first and second linear rails having first and second mounting surfaces coupled to the respective first and second walls; the linear rails oriented so that the respective first and second load directions are oriented normal to and apply a tensile load to the respective mounting surfaces.

12. The patient handling system of claim 5, further comprising a continuous planar, flexible belt covering the open cavity, respective longitudinal ends of the belt coupled to respective longitudinal ends of the frame, the belt passing between opposed rollers that are coupled to the trolley.

13. The patient handling system of claim 12, the frame further comprising first and second drip rails coupled to the outer surface of the frame along lateral edges of the cavity, below lateral edges of the flexible belt.

14. The patient handling system of claim 5, the frame further comprising floor mounting lugs coupled to outer facing surfaces of the first and second walls.

15. The patient handling system of claim 5, further comprising a drag chain oriented in the cavity for providing electrical power to the linear motor and / or the trolley, one end of the drag chain coupled to the frame and the other end of the drag chain coupled to the trolley.

16. A patient handling system for a medical imaging apparatus, comprising: a frame with a longitudinal length, defining a central longitudinal axis and an upper surface, having: opposed, laterally spaced, outer first and second walls, commonly joined and bridged by a transverse-oriented third wall; fourth and fifth walls oriented inboard of the first and second walls that are commonly coupled by the transverse third wall, all of said first through fifth walls parallel to the central longitudinal axis, the third, fourth and fifth walls collectively defining a u-shaped, open cavity that is in communication with the upper surface of the frame; a transverse oriented sixth wall joining the outer, first wall and the inboard, fourth wall, and a transverse oriented seventh wall joining the outer, second wall and the inboard, fifth wall; the sixth and seventh walls forming lateral edges of the cavity that are parallel to the longitudinal axis; the frame constructed as a metal monolithic block, formed by a metal extrusion process; first and second linear rails respectively coupled to the respective first and second walls, oriented parallel to the central longitudinal axis; first and second runner blocks, respectively slidably coupled to the first and second linear rails; a trolley commonly coupled to the first and second runner blocks, the trolley slidably mounted over the upper surface of the frame and translatable along the central longitudinal axis; a cantilevered patient bed coupled to the trolley, so that weight load of the patient bed is transferred to the frame along a first load direction through the trolley, the first runner block and the first linear rail and along a second load direction through the trolley, the second runner block and the second linear rail; at least one linear motor having a rotor and a linear stator in opposed orientation, separated by a motor gap, the rotor coupled to the trolley by a motorsupport extending into the cavity, and the linear stator coupled to the fourth wall or the fifth wall, in orientation parallel to the central longitudinal axis, with the motor gap onented parallel to at least one of the first and second load directions; and at least one linear motion encoder, having a sensing head and a linear encoder tape in opposed orientation, separated by an encoder gap, the sensing head coupled to the trolley or one of the first or the second runner blocks and the linear encoder coupled to the frame in orientation parallel to the frame central longitudinal axis, with the encoder gap oriented parallel to at least one of the first or second load directions.

17. The patient handling sy stem of claim 16, further comprising the first and second linear rails having respective first and second mounting surfaces coupled to the respective first and second walls; the first and second linear rails oriented so that the respective first and second load directions are parallel to and apply a shearing load on the respective mounting surfaces.

18. The patient handling system of claim 16, further comprising the first and second linear rails having first and second mounting surfaces coupled to the respective first and second walls; the linear rails oriented so that the respective first and second load directions are oriented normal to and apply a tensile load to the respective mounting surfaces.

19. The patient handling system of claim 16, further comprising: a continuous planar, flexible belt covering the open cavity, respective longitudinal ends of the belt coupled to respective longitudinal ends of the frame, the belt passing between opposed rollers that are coupled to the trolley; and a first drip rail coupled to the sixth wall, and a second drip rail coupled to the seventh wall, both drip rails coupled to the outer surface of the frame along lateral edges of the cavity, below lateral edges of the flexible belt.

20. The patient handling system of claim 16, further comprising a drag chain oriented in the cavity for providing electrical power to the linear motor and / or the trolley, one end of the drag chain coupled to the frame and the other end of the drag4 chain coupled to the trolley.

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